Table I.

Disc degeneration characteristics as determined by T2-weighted magnetic resonance imaging.

Grade	Structure	Nucleus and annulus distinction	Signal intensity	Height of intervertebral disc
I	Homogeneous, bright white	Clear	Hyperintense, isointense to cerebrospinal fluid	Normal
II	Inhomogeneous with or without horizontal bands	Clear	Hyperintense, isointense to cerebrospinal fluid	Normal
III	Inhomogeneous, gray	Unclear	Intermediate	Normal to slightly decreased
IV	Inhomogeneous, gray to black	Absent	Intermediate to hypointense	Normal to moderately decreased
V	Inhomogeneous, black	Absent	Hypointense	Collapsed disc space